Floor-sanding machine



Dec.. 10, 1929. R. -E. DE WALT FLOOR SANDING MACHINE Filed July 31, 1926 2 Sheets-Sheet Dec; 10, 1929. R. E. DE WALT I FLOOR'SANDING MACHINE Filed July 31, 1926 2 Sheets-Sheet 2 "m 5 i: :1? r.

Patented Dec. 10, 1929 I UNITED STATES PATENT OFFICE Application filed July 31, 1926. Serial No.'126,169.

This invention relates to an electrically shaft 11 of the motor is non-rotatably sedriven machine for surfacing, sanding or polcured tothe side frames, and the condiictors ishing floors, and aims to provide an easily feeding current to the motor are led through portable machineof simple and efficient conthe shaft as indicated in Fig. 3. The rotatstruction. I able outer shell of the motor is of substantial- A feature of the invention resides in the ly the same height as the side frames, and acts utilisation of an electric motor of the type in as a pulley to support the rear end of the which the central core remains stationary abrasive belt 13, which is of any suitablemae and the outer shell revolves. This revolving terial coated with sand, carborundum, or motor shell is used as a pulley for moving the other abrasive. The forward end of the endless abrasive belt which passes over a secdrive belt passes around a roller 14 journaled 0nd pulley and a suitably mounted idler. A between the forward ends of the side frames, movable presser plate, which is adapted to while a spring-pressed idler 15 is provided move the abrasive belt into contact with the for taking the slack out of belt 13. The idler floor surface to be treated, is controlled by a is mounted on a carriage 16 pivoted on the GO trigger in such a manner that the trigger may shaft 17 and a coiled spring 18 surrounds the be manipulated to vary the pressure with shaft and presses the idler upward against which the belt is applied to the floor. the under side of the belt. I

The invention also includes apower-driven A cross member 19 extends between the 20 fan for collecting the dust inevitably created central part of the side frames and braces 65 by the surfacing mechanism. them in proper spaced relation. The lower Other features and objects of the invention edge of each side frame carries a hard wood will becomeapparent as the description prorunner 20, the runners being adapted to slide ceeds. across the floor surface under treatment and ment for purposes of illustration, it should the machine. Most of the weight of the mobe understood that various changes may be tor is carried by two wheels 21 mounted at made without departing from the spirit and the rear of the side frames. Handle memscope of the invention as hereinafter set forth here 22 and 23 are attached to the side frames and claimed. and provide means by which the machine is 75 In the drawings, controlled, the motor switch 37 being Fig. 1 is a side elevation of the machine, mounted on the handle members. parts being broken away; The parts are so arranged that when the Fig. 2 is an elevation of the upper end of machine is in position on a floor surface, as the handle; in Fig. 1, the abrasive belt is parallel to the 30 Fig. 3 is a plan view, parts being broken floor but is normally spaced therefrom.

. away; Means are provided by which the operator Fig. f is adetail plan of the presser plate; can move the belt into contact with the door Fig. 5 is a detailed elevation of the attachat will. These means include the presser ment of one side of the handle to the body of plate El ipivotally mounted on the arm 25 of the machine. a bell crank, the shaft 26 of which passes Referring to the drawings more specificalthrough a lug 27 depending from the cross ly, the body of the machine is composed of member 19 and after extending through the two side frames 10 between the rear ends of side frame 10 carries an operating arm 28.

l/Vhile I have disclosed a preferred embodito carry the weight of the forward part of a which the motor is mounted. The hollow A control rod 29 is attached to the outer end v of arm 28, extends along the handle member 22 and is connected to a; tri ger pivoted below the hand piece 31. flat spring 32 is mounted between the hand piece 31 and the trigger 30 and tends to normally hold the presser plate 24 in elevated position. By pressing the trigger toward the hand piece the operator can depress the resser plate, causing the belt to engage t e floor, the amount of pressure with which the belt engages the floor depending upon the amount of pressure applied to the t; 'tgger.

In order to collect the dust caused by the abrading mechanism, a sheet metal cover '33 closes the rear end of the machine and carries'a motor-driven suction fan 34, the latter discharging into a collection bag 35. The

. cover 33 together with the runners 20 provides a dust-tight casing surrounding the point of work and causes the dust to move in the direction of travel of the belt; i. e., toward the suction fan 34.

Wheneverit becomes necessary to replace a worn belt or to change the character of the abrading surface, the belt can readily be removed. To permit such removal the cover 33 is remova ly attached by a plurality of thumb screws 35 and the left handle can be separated at the hinge 36. After the cover has been removed as shown in Fig. 5 the hinge 36 is opened and the belt can be slipped off on this side of the machine.

It will be noted that in the operation of the machine the runners 20 serve as bumpers to keep the machine from marring the woodwork. The operator has complete and extremely sensitive control over the working pressure at all times and because of the large flat area of the pressure plate the machine produces a floor area free from furrows or ridges.

I claim: I

1. In a sandingimachine, a air of side frame plates, a motor roller tween the plates at the rear thereof, an idler roller between the plates at the front thereof, a press- .er plate between said plates intermediate of thelower parts of the rollers a rock shaft extending .across the device from one. side plate to the middle of the machine, a rock arm plate to the middle of the machine, a rock arm on the inner end of the rock shaft and pivotally connected to the presser plate at its center, a second rock arm on the outer end of the rock shaft, a handle projecting upwardly. from the side plate, an operating lever on said handle, a link connecting the second rock arm and lever, a sander belt extending around said rolls and under said plate, and means to maintain constant tension on said sander belt.

- In testimony whereof I afiix mysi nature.

' RAYMOND E. DE ALT.

on the inner end of therock shaft and pivotally connected to the presser. plate at its center, a second rock arm on the outer end of the rock shaft, a handle, projecting u wardly from the side plate, an operating said handle, rock arm and lever, and asander beltextendmg around.said rolls and under said plate.

2. In a sanding machine, a air of side frame; plates, 'a motor roller tween the er plate between said plates intermediate of the lower parts of the rollers a rock shaft extending across the device mone'eide ever on a link connecting the second- 'platesat the rear thereof, an idler roller be- 1 tween theplates at the front thereof, a press- 

